Reducing connection validation (CV) time in an optical node

ABSTRACT

Systems and methods for conducting various types of Connection Validation (CV) are provided for reducing the overall CV scan time of regular CV scans. A method, according to one implementation, includes a step of receiving a request to perform a focused CV on one or more communication cables after the one or more communication cables are physically connected or reconnected into a portion of a network. The method also includes the steps of interrupting an ongoing CV running in the portion of the network and executing the focused CV to target a CV scan on the one or more communication cables.

TECHNICAL FIELD

The present disclosure generally relates to optical networking systemsand methods. More particularly, the present disclosure relates torunning Connection Validation (CV) scans that are focused on specificcommunication cables subsequent to these communication cables beingconnected or reconnected in a Reconfigurable Optical Add/DropMultiplexer (ROADM) of an optical network.

BACKGROUND

When network elements (e.g., ROADM nodes) are deployed in an opticalcommunication network, CV methods may normally be performed to verifythe inter-degree and/or add/drop-to-degree fiber connections. Thisverification is performed in order to ensure that the optical fibers areconnected to the proper ports and that the measured fiber loss is withinexpected limits. CV scans may be run in any type of network environment,such as in a full homogeneous network where there is communicationbetween interconnected degrees, in a disaggregated configurations(heterogeneous network) where there is no communication between shelvesor interconnected cards, or other suitable types of networks. Forexample, a homogeneous network may include equipment from the samevendor, thereby having communication between the degrees. On thecontrary, a disaggregated configuration may include equipment fromdifferent vendors, thereby having no communication.

With a CV scan, a signal source (Tx) is typically implemented per ROADMdegree or per channel mux/demux and is configured to cycle through eachinterconnected fiber transmit port. As described herein, the term “mux”refers to a multiplexer whereas a “demux” refers to a demultiplexer.Also, the Tx source signal is transmitted with a protocol message thatuniquely identifies the originating port ID (e.g., the Tx port ID), aswell as that port's total output power. On a far end of the ROADM, areceiver (Rx) cycles through each of its receiving ports (Rx ports) tocatch the CV packets transmitted from the source end of the ROADM. Thereceiver (Rx) has to wait (e.g., Rx dwell time) on each port long enoughso that it can reliably catch the transmitted packets. This means that,if a ROADM site is built with Wavelength Selective Switching (WSS) andhas N number of degrees and add/drop ports, then:

-   -   a) for N number of ports, the Rx dwell time would be equal to        about N*Tx dwell time, and    -   b) the total CV cycle time would be equal to about N²*Tx dwell        time.        Thus, for a typical Tx dwell time of one second and a typical        configuration of N=32 (e.g., for an 1×32 WSS), the CV cycle time        would be equal to 32²*one second, which is about 17 minutes.        During maintenance of an optical network, if optical cables are        disconnected and then reconnected, this one CV scan would        require about 17 minutes, which, in many situations, is an        unacceptably long time.

Additionally, in a typical deployment, however, decoding data over oneCV cycle time sometimes provides erroneous outcomes. For example, as aresult of limited port-to-port isolation in a WSS, a lower powerinstance of the signal might be transmitted or received on an unintendedport. These unintended signal artifacts may be referred to as “ghosts.”To alleviate the ghost packet manifestations, CV implementations mayrequire a second scanning process of all the ports and then picking upthe packets from a transmit port appearing with the least amount oflosses (or the highest power). Hence, the total CV processing time (orCV cycle time) would be equal to about 17 minutes*2 scan cycles=34minutes. That means, with existing techniques, if a Multi-fiber Push On(MPO) fiber is disconnected and then reconnected (or during initialinstallation), the user (e.g., technician, installer, maintenanceoperator, engineer, network operator, or other users), in order toreceive connection validation and fiber loss detection, may be requiredto wait for two full cycles, which could take over 30 minutes tocomplete. occur, which is typically considered to be an unacceptableamount of time from the perspective of service and deployment teams.

Since there is usually no coordination between the transmit and receiveends regarding CV scans, it normally takes a long time to scan a singlefiber or sub-fiber in a Multi-fiber Push-On (MPO) type of cable. Again,on a typical 1×32 ROADM configuration, it takes about 17 minutes toperform a single scan and can take up to about 34 minutes in a worstcase scenario run a second scan to alleviate any ghost packetnotifications in the ROADM. Therefore, there is a need in the field ofcommunication networks (e.g., optical networks) to provide CV scanningprocesses that improve upon the existing strategies and can reduce theoverall CV run time to more quickly and efficiently utilize atechnician's operations times.

BRIEF SUMMARY

The present disclosure is directed to optical networks and controlsystems for running Connection Validation (CV) scans on communicationcables within a node of the optical networks. More particularly, thecontrol systems as described in the present disclosure are configured torun the CV scans after an optical cable (or Multi-fiber Push-On (MPO)connector cable) is inserted into a node (e.g., Reconfigurable OpticalAdd/Drop Multiplexer (ROADM)) of the optical network. Normally,conventional CV scans may be designed to run continuously to constantlycheck that the optical cables are connected properly to allow the ROADMto communicate with other components in the optical network in asatisfactory manner.

According to one embodiment of the present disclosure, a controller(configured to manage CV processes in a portion of a network) mayinclude an interface configured to interact with a network node arrangedin the portion of the network. The controller may also include aprocessing device in communication with the interface and a memorydevice in communication with the processing device. The memory devicemay be configured to store a computer program having instructions that,when executed, enable the processing device to receive a request toperform a focused CV on one or more communication cables after the oneor more communication cables are physically connected or reconnectedinto the network node arranged in the portion of a network. In addition,the instructions further enable the processing device to interrupt anongoing CV running in the portion of the network and execute the focusedCV to target a CV scan on the one or more communication cables.

According to another embodiment of the present disclosure, a method mayinclude the step of receiving a request to perform a focused CV on oneor more communication cables after the one or more communication cablesare physically connected or reconnected into a portion of a network. Themethod may also include the steps of interrupting an ongoing CV runningin the portion of the network and executing the focused CV to target aCV scan on the one or more communication cables.

According to yet another embodiment of the present disclosure, anon-transitory computer-readable medium may be configured to storecomputer logic for performing CV scans. The computer logic may includeinstructions that are configured to enable a processing device toreceive a request to perform a focused CV on one or more communicationcables after the one or more communication cables are physicallyconnected or reconnected into a portion of a network. The computer logicmay further include instructions configured to enable the processingdevice to interrupt an ongoing CV running in the portion of the networkand execute the focused CV to target a CV scan on the one or morecommunication cables.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated and described herein withreference to the various drawings. Like reference numbers are used todenote like components/steps, as appropriate. Unless otherwise noted,components depicted in the drawings are not necessarily drawn to scale.

FIG. 1 is a schematic diagram illustrating at least a portion of aReconfigurable Optical Add/Drop Multiplexer (ROADM) within which varioustypes of Connection Validation (CV) scans may be executed, according tovarious embodiments of the present disclosure.

FIG. 2 is a block diagram illustrating a controller for executing CVscans in the ROADM of FIG. 1, according to various embodiments of thepresent disclosure.

FIG. 3 is a schematic diagram illustrating a section of the ROADM ofFIG. 1 for focusing a CV scan on a targeted Multi-fiber Push-On (MPO) ofthe ROADM, according to various embodiments of the present disclosure.

FIG. 4 is a flow diagram illustrating a process for performing a CV scanfocused on an MPO of a ROADM, according to various embodiments of thepresent disclosure.

FIGS. 5A and 5B are schematic diagrams illustrating another section ofthe ROADM of FIG. 1 for executing a full-node, optimized CV scan foravoiding known good connections to reduce CV processing times, accordingto various embodiments of the present disclosure.

FIG. 6 is a graph illustrating the CV reception power reading related toexecuting the CV scan with respect to FIG. 5, according to variousembodiments of the present disclosure.

FIG. 7 is a diagram illustrating the transmission of port identification(port ID) with respect another CV scan that involves skippingnon-provisioned Tx and Rx ports, according to various embodiments of thepresent disclosure.

FIG. 8 is a schematic diagram illustrating another section of the ROADMof FIG. 1 for executing another CV scan that involves skipping unusedports by utilizing loopback connectors, according to various embodimentsof the present disclosure.

FIG. 9 is a chart illustrating expected times for running the various CVscans on the ROADM of FIG. 1, according to various embodiments of thepresent disclosure.

DETAILED DESCRIPTION

The present disclosure relates to systems and methods for controlling CVprocesses within a network element or node of a communication system(e.g., optical network). As mentioned above, typical CV scans may be runin the node to check the validation of connections to ensure that cablesare linked to the proper ports and that the signal loss across thecables is within acceptable tolerances. These typical CV scans maynormally run on an ongoing or continuous basis. However, as mentionedabove, each CV scan may require an unacceptably large amount of time tocomplete. Therefore, the embodiments of the present disclosure areconfigured to perform other specific types of CV scans that can be moreefficient to thereby complete the CV processes in a fraction of thenormal processing times for conventional CV scans.

In particular, the embodiments of the present disclosure are configuredto detect when one or more communication cables (e.g., Multi-fiberPush-On (MPO) connector cables) are newly installed in a node of anoptical network or have been disconnected for maintenance purposes(e.g., for dusting or cleaning the cables) and then reconnected againwithin the nodes. It may be important at this time to determine that thecables are properly installed back into the node such that theconnectors properly engage the corresponding connectors on the node andthat the cables are plugged into the correct ports. For example, a CVscan may be run after maintenance, such as after detection of a badconnection, misconnection, high fiber loss, or other similar problem Atechnician may remove a MPO cable to clean it up, but once the MPO cableis reinstalled, the technician may be required to wait up to 34 minutesjust to see if the cable is correct or not, which is normallyunacceptable in this situation.

Therefore, the embodiments of the present disclosure are configured tofocus a new CV scan on the particular cable or cables that have justbeen reconnected, reattached, or reinstalled. Thus, subsequent toreconnection, the CV techniques described in the present disclosure maybe run to provide the benefit of a reduced CV processing time amongother benefits as will be recognized by one or ordinary skill in the arthaving an understanding of the spirit and scope of the embodiments ofthe present disclosure.

With Reconfigurable Optical Add/Drop Multiplexer (ROADM) nodes deployedin an optical network, CV methods are configured to verify the fiberconnections between degrees and/or fiber connections between a degreeand an add/drop device. The CV methods are configured to verify orensure that the fibers are connected to the proper ports and themeasured fiber loss is below a predetermined threshold. The ROADM nodesmay be deployed in networks having either a homogeneous or disaggregated(heterogeneous) configuration.

The embodiments of the present disclosure are configured to rundifferent types of CV scans that differ from conventional CV methods.For example, the present embodiments do not cycle through every Tx portand every Rx port, as is normally done in the conventional systems.Instead, the embodiments described herein use a more judicious approachwhereby CV scanning before Tx ports and Rx ports can be focused ortargeted to just the cables that may need to be checked. In other words,if certain cables remain unchanged during a maintenance procedure, thereis no immediate need to recheck the connection for these cables.However, after one or more cables have been reconnected in the network,the embodiments of the present disclosure may detect this recentreconnection status (or may receive a request from an operator to checkthese cables). Then, one or more of the focused or targeted CV scansdescribed herein may be executed to check the connectivity and signalloss of just these cables.

Also, some of the embodiments of the present disclosure may beconfigured to utilize a leader/follower approach, which furtherdistinguishes from the conventional systems that may be designed with nounique identifier for a shelf or chassis. In the leader/followerapproach, an identifier may be used among the interconnected degrees oradd/drop shelves. Also, the present disclosure provides a centralizedcontroller that can coordinate CV actions between the shelves.Furthermore, the present embodiments may include a dependency on asingle ROADM degree or node element (e.g., a centralized dependency on aspecific Fiber Interconnect Module (FIM) as described in someimplementations).

Conventional asynchronous CV implementation may assume that a networkincludes fully populated MPO ports and includes a disaggregatedconfiguration where there is no communication between shelves. However,this is not always the case for many deployed ROADM configurations. Thepresent disclosure takes advantage of the presence of any inter-shelfcommunication between any interconnected degree or add/drop shelves anddetects partial fill degree connections to reduce the total CV cycletime.

Several example methods are presented in this disclosure to address thereduction of CV cycle time. For example, one implementation may includedetecting Tx ports that are unused or already in service (e.g., alreadycarrying traffic signals) and does not transmit on those unused orin-service Tx ports. Another implementation may include detecting unusedor in-service Rx ports and avoiding CV scans through them. Yet anotherimplementation may include populating unused ports with loopbackconnectors so that a network card can quickly and independentlydetermine which ports are unused.

These and other implementations include techniques to reduce Rx dwelltime (which is a function of the number of Tx ports and the Tx dwelltime) and further includes sending additional Tx information via thetransmit protocol message, whereby the additional information mayinclude the number of Tx ports in use, the Tx dwell time, the total Txscanning time, among other parameters. In addition, the “ghost signaldetection,” which filters out false connections due to WSS crosstalk,are further optimized to identify “known good connections” immediately,rather than waiting until the end of the full CV cycle. With the systemsand methods described herein, a typical four-degree connected ROADM nodemay be expected to take only about one minute to scan to provide asummary CV report for all interconnected ports. Also, a specific MPOport (and all of its sub-fibers) after repair/maintenance can beexamined in less than 10 seconds by the present systems and methods,compared to conventional methods that may take up to about 34 minutes.

There has thus been outlined, rather broadly, the features of thepresent disclosure in order that the detailed description may be betterunderstood, and in order that the present contribution to the art may bebetter appreciated. There are additional features of the variousembodiments that will be described herein. It is to be understood thatthe present disclosure is not limited to the details of construction andto the arrangements of the components set forth in the followingdescription or illustrated in the drawings. Rather, the embodiments ofthe present disclosure may be capable of other implementations andconfigurations and may be practiced or carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed are for the purpose of description and should not be regardedas limiting.

As such, those skilled in the art will appreciate that the inventiveconception, upon which this disclosure is based, may readily be utilizedas a basis for the designing of other structures, methods, and systemsfor carrying out the several purposes described in the presentdisclosure. Those skilled in the art will understand that theembodiments may include various equivalent constructions insofar as theydo not depart from the spirit and scope of the present invention.Additional aspects and advantages of the present disclosure will beapparent from the following detailed description of embodiments whichare illustrated in the accompanying drawings.

FIG. 1 is a schematic diagram illustrating an embodiment of portions ofa Reconfigurable Optical Add/Drop Multiplexer (ROADM) 10 that isemployed as an optical node in an optical network. In the ROADM 10, aswith other types of optical nodes, various types of ConnectionValidation (CV) techniques may be used for scanning the node in order todetermine if the connections within the node are acceptable. As shown inFIG. 1, the ROADM 10 includes at least one degree component 12 (e.g., aWavelength Selective Switching (WSS) component) and at least oneadd/drop component 14. The degree component 12 includes a demultiplexer16 for receiving optical signals along a single ingress path 20 at aspecific degree and a multiplexer 18 for transmitting optical signalsalong a single egress path 22 at the specific degree. The add/dropcomponent 14 includes demultiplexers 24 and multiplexers 26 for removing(dropping) and adding optical channels according to normal ROADMoperations. According to other embodiments, the ROADM may includemultiple degrees and multiple add/drop components.

In addition to typical ROADM adding and dropping processes, CV scans arealso run to check the connectivity throughout the ROADM 10. To run a CVscan, a CV source 28 (Tx) inserts CV scan signals that cycle through theoutput ports 30-1, 30-2, . . . , 30-N of the demultiplexer 16. The CVsource 28 may be photodiode for providing a light signal containinginformation for the CV test. Each output port 30 is associated with acorresponding demultiplexer of one of the demultiplexers 24 of theadd/drop component 14. In this way, each CV signal from a respectiveoutput port 30 is applied to the sets of output ports 32 of thedemultiplexers 24. Each of the demultiplexers 24 includes a CV receiver34 (Rx) for receiving the CV signals from the CV source 28. The CVsource 28 transmits the CV signals using a protocol that uniquelyidentifies the originating port IDs of the respective output ports 30-1,30-2, . . . , 30-N. Also, the CV protocol includes embedding the outputpower at the respective output port 30 in the CV signal. The ROADM CVsignal power may be for dark fibers only or may include ROADM CV+trafficsignal power otherwise.

Each of a plurality of CV receivers 34 (e.g., photodiodes) cyclesthrough the respective input ports 36-1, 36-2, . . . , 36-N and dwellslong enough on any given port such that it will capture the CV scansignal from the CV source 28 as it cycles at the add/drop end of theROADM 10. The first CV receiver 34 is also configured to decode theoriginating port ID and the originating Tx power and may then comparethis information to expected adjacencies and inter-pack losses. With Nports (i.e., N output ports 30 and N input ports 36), the amount of timethat the first CV receiver 34 scans for signals, which may be referredto as “dwell time,” may be estimated by the following:Rx_dwell_time=˜N*Tx_dwell_timewhere Tx_dwell_time is the amount of time that each output port 30continues to transmit to ensure that each input port 36, in sequence,has a chance to check connectivity (if any) thereto. Thus, the followingdefines the total time that it takes to perform the CV scan:Total CV cycle time=˜N ² *Tx_dwell_timeAs an example, if the Tx_dwell_time is equal to one second and N=32, theTotal CV cycle time will be about 17 minutes.

Also, the ROADM 10 includes a set of CV sources 38 configured for eachmultiplexer of the multiplexers 26. In a similar procedure, the CVsources 38 apply CV scans in sequence to multiple sets of input ports 40for multiple multiplexers. These CV scans are applied to respectiveoutput ports 42-1, 42-2, . . . , 42-N of the multiplexers 26 andtransmitted to input ports 44-1, 44-2, . . . , 44-N of the multiplexer18. An egress port of the multiplexer 18 is associated with a CVreceiver 46 configured to decode the CV signals from each of the CVsources 38 transmitted in a direction from the add/drop component 14 tothe degree component 12, which is the opposite direction with respect tothe first CV scan from the CV source 28 of the degree component 12 to CVreceivers 34 of the add/drop component 14.

Proposed High-Level Method

As suggested above, it may be unacceptable for a technician to berequired to wait 17 minutes or longer for a CV scan to run duringmaintenance of an optical node. Therefore, in order to reduce the TotalCV cycle time, different approaches are proposed in the presentdisclosure, each of which may reduce the cycle time by different amount.Each of the techniques described in the present disclosure may beadvantageous over conventional methods, although some may be able toreduce the processing time more significantly.

It has been noted that conventional asynchronous CV implementations maytypically assume fully populated Multi-fiber Push-On (MPO) ports and adisaggregated architecture where there is no communication betweenshelves. However, if inter-shelf communication is available, oneimplementation of the present disclosure includes taking advantage ofthis communication and allow the ports to be only partially filled,according to the actual need. As such, the Total CV cycle time can bereduced by eliminating one or more unnecessary steps. For example, thecycle time can be reduced by:

-   -   1) not transmitting to unused or in-service Tx ports;    -   2) not scanning unused or in-service Rx ports;    -   3) reducing the Rx dwell time, which is a function of the number        of Tx ports and the Tx_dwell_time; and/or    -   4) optimizing the “ghost channel algorithm,” which filters out        false connections due to WSS crosstalk to identify “known good        connections” immediately, rather than wait until the end of a        full CV cycle.

Traditionally, CV pass/fail may be inferred by the presence or lack ofalarms. A complementary objective to the performance improvements in thepresent disclosure may be to provide a consolidated summary (includinglast scanned time-stamps) for better usability in interpreting results.

Some of the challenges to be overcome by the proposed techniques mayinclude the case where there may be no site master shelf, so that anysynchronization may need to be done via a peer-to-peer communication.Also, since there is no centralized coordinator, providing aconsolidated site summary may be more challenging. Furthermore,knowledge about whether each port is actually used or not may be basedon provisioning, and thus there could be a corner case blind spots ifphysical install is misaligned with provisioning.

FIG. 2 is a block diagram illustrating an embodiment of a controller 50for executing CV scans in an optical node, such as the ROADM 10 ofFIG. 1. In the illustrated embodiment, the controller 50 may be adigital computer that, in terms of hardware architecture, generallyincludes a processing device 52, a memory device 54, Input/Output (I/O)interfaces 56, and an interface 58. The memory device 54 may include adata store, database, or the like. It should be appreciated by those ofordinary skill in the art that FIG. 2 depicts the controller 50 in asimplified manner, where practical embodiments may include additionalcomponents and suitably configured processing logic to support known orconventional operating features that are not described in detail herein.The components (i.e., 52, 54, 56, 58) are communicatively coupled via alocal bus 62. The local bus 62 may be, for example, but not limited to,one or more buses or other wired or wireless connections. The local bus62 may have additional elements, which are omitted for simplicity, suchas controllers, buffers, caches, drivers, repeaters, receivers, amongother elements, to enable communications. Further, the local bus 62 mayinclude address, control, and/or data connections to enable appropriatecommunications among the components 52, 54, 56, 58.

The processing device 52 is a hardware device adapted for at leastexecuting software instructions. The processing device 52 may be anycustom made or commercially available processor, a Central ProcessingUnit (CPU), an auxiliary processor among several processors associatedwith the controller 50, a semiconductor-based microprocessor (in theform of a microchip or chip set), or generally any device for executingsoftware instructions. When the controller 50 is in operation, theprocessing device 52 may be configured to execute software stored withinthe memory device 54, to communicate data to and from the memory device54, and to generally control operations of the controller 50 pursuant tothe software instructions.

It will be appreciated that some embodiments of the processing device 52described herein may include one or more generic or specializedprocessors (e.g., microprocessors, CPUs, Digital Signal Processors(DSPs), Network Processors (NPs), Network Processing Units (NPUs),Graphics Processing Units (GPUs), Field Programmable Gate Arrays(FPGAs), and the like). The processing device 52 may also include uniquestored program instructions (including both software and firmware) forcontrol thereof to implement, in conjunction with certain non-processorcircuits, some, most, or all of the functions of the methods and/orsystems described herein. Alternatively, some or all functions may beimplemented by a state machine that has no stored program instructions,or in one or more Application Specific Integrated Circuits (ASICs), inwhich each function or some combinations of certain of the functions areimplemented as custom logic or circuitry. Of course, a combination ofthe aforementioned approaches may be used. For some of the embodimentsdescribed herein, a corresponding device in hardware and optionally withsoftware, firmware, and a combination thereof can be referred to as“circuitry” or “logic” that is “configured to” or “adapted to” perform aset of operations, steps, methods, processes, algorithms, functions,techniques, etc., on digital and/or analog signals as described hereinfor the various embodiments.

The I/O interfaces 56 may be used to receive user input from and/or forproviding system output to one or more devices or components. User inputmay be provided via, for example, a keyboard, touchpad, a mouse, and/orother input receiving devices. The system output may be provided via adisplay device, monitor, Graphical User Interface (GUI), a printer,and/or other user output devices. I/O interfaces 56 may include, forexample, one or more of a serial port, a parallel port, a Small ComputerSystem Interface (SCSI), an Internet SCSI (iSCSI), an AdvancedTechnology Attachment (ATA), a Serial ATA (SATA), a fiber channel,InfiniBand, a Peripheral Component Interconnect (PCI), a PCI eXtendedinterface (PCI-X), a PCI Express interface (PCIe), an InfraRed (IR)interface, a Radio Frequency (RF) interface, and a Universal Serial Bus(USB) interface.

The interface 58 may be used to enable the controller 50 to communicatewith and interact with a network node or device (e.g., ROADM 10) or tocommunicate over a network, such as an optical network that includes theROADM 10 or other network (e.g., the Internet, a Wide Area Network(WAN), a Local Area Network (LAN), etc.). The interface 58 may include,for example, an Ethernet card or adapter (e.g., 10BaseT, Fast Ethernet,Gigabit Ethernet, 10 GbE) or a Wireless LAN (WLAN) card or adapter(e.g., 802.11a/b/g/n/ac). The interface 58 may include address, control,and/or data connections to enable appropriate communications on thenetwork.

The memory device 54 may include volatile memory elements (e.g., RandomAccess Memory (RAM)), such as Dynamic RAM (DRAM), Synchronous DRAM(SDRAM), Static RAM (SRAM), and the like, nonvolatile memory elements(e.g., Read Only Memory (ROM), hard drive, tape, Compact Disc ROM(CD-ROM), and the like), and combinations thereof. Moreover, the memorydevice 54 may incorporate electronic, magnetic, optical, and/or othertypes of storage media. The memory device 54 may have a distributedarchitecture, where various components are situated remotely from oneanother, but can be accessed by the processing device 52. The softwarein memory device 54 may include one or more software programs, each ofwhich may include an ordered listing of executable instructions forimplementing logical functions. The software in the memory device 54 mayalso include a suitable Operating System (O/S) and one or more computerprograms. The O/S essentially controls the execution of other computerprograms, and provides scheduling, input-output control, file and datamanagement, memory management, and communication control and relatedservices. The computer programs may be configured to implement thevarious processes, algorithms, methods, techniques, etc. describedherein.

The memory device 54 may include a data store used to store data. In oneexample, the data store may be located internal to the controller 50 andmay include, for example, an internal hard drive connected to the localbus 62 in the controller 50. Additionally, in another embodiment, thedata store may be located external to the controller 50 and may include,for example, an external hard drive connected to the Input/Output (I/O)interfaces 56 (e.g., SCSI or USB connection). In a further embodiment,the data store may be connected to the controller 50 through a networkand may include, for example, a network attached file server.

Moreover, some embodiments may include a non-transitorycomputer-readable storage medium having computer readable code stored inthe memory device 54 for programming the or other processor-equippedcomputer, server, appliance, device, circuit, etc., to perform functionsas described herein. Examples of such non-transitory computer-readablestorage mediums include, but are not limited to, a hard disk, an opticalstorage device, a magnetic storage device, a Read Only Memory (ROM), aProgrammable ROM (PROM), an Erasable PROM (EPROM), and ElectricallyErasable PROM (EEPROM), Flash memory, and the like. When stored in thenon-transitory computer-readable medium, software can includeinstructions executable by the processing device 52 that, in response tosuch execution, cause the processing device 52 to perform a set ofoperations, steps, methods, processes, algorithms, functions,techniques, etc. as described herein for the various embodiments.

According to some embodiments, the controller 50 may include a focusedConnection Validation (CV) scanning module 64. In some embodiments, thefocused CV scanning module 64 may be implemented as software and storedin the memory device 54. In other embodiments, the focused CV scanningmodule 64 may be implemented, at least partially, as hardware andconfigured as an ASIC or other hardware element and operated by theprocessing device 52. According to other embodiments, the focused CVscanning module 64 may include any combination of hardware, software,and/or firmware and include computer logic or instructions for enablingthe processing device 52 to perform various CV scanning functions.

In particular, the focused CV scanning module 64 may enable theprocessing device 52 to perform a CV scan that is focused only oncertain ports, while avoiding other unused or currently-active ports. Byavoiding these ports, it is possible to significantly reduce the CV scantime for a technician or troubleshooter. In some embodiments, thefocused CV scanning module 64 may be configured to include logic thatincludes receiving a request to perform a focused CV for targeting a CVscan on one or more communication cables after these cables haverecently been physically connected to reconnected to a portion of anetwork. In response to this request, the focused CV scanning module 64may include interrupting any ongoing CV methods that may be continuouslyrunning in this portion of the network. Also, the instructions of thefocused CV scanning module 64 may further include executing the focusedCV on just the one or more communication cables. Upon completion of thefocused CV, the focused CV scanning module 64 may be configured to allowthe interrupted CV methods to resume again, having been interrupted bythe focused CV scan.

Focusing a CV Scan on a Targeted MPO Cable

FIG. 3 is a schematic diagram illustrating an embodiment of a section 70of the ROADM 10 of FIG. 1. In this embodiment, the section 70 is shownto emphasize a process for performing a focused CV scan on a targetedMulti-fiber Push-On (MPO) of the ROADM 10. For example, the focused CVscan may be run after a maintenance event (e.g., repair that involvesremoving and reconnecting an MPO). The section 70, according to thisexample arrangement, includes eight Line Amplifier (LA) components 72-1,72-2, . . . 72-8 configured to communication with eightMultiplexer/Demultiplexer (MD) components 74-1, 74-2, . . . , 74-8.

The LA components 72 may be configured with one input and 32 outputs(1×32) or other suitable I/O arrangement. The LA components 72 may beC-band modules or C+L-band modules with double width and single height.Also, the LA components 72 may be configured with a flexible grid WSS,dual-line EDFA, bi-directional OTDR, integrated ASE, optical channelmonitoring, and Optical Service Channel (OSC) for high port count ROADMapplications. The MD components 74 may be configured as circuit packswith eight inputs and 24 outputs (8×24), 8×16, or other suitable I/Oarrangement. The MD components 74 may be C-band modules or C+L-bandmodules with single width and double height. The MD components 74 mayhave twin contentionless WSSs for interconnecting add/drop channels toany of eight degrees for ROADM applications.

Connections between the LA components 72 and MD components 74 mayinclude MPO connector cables, which may include Fiber InterconnectModules (FIMs) A FIM is a module that includes fixed cable connectionsand is used to reduce the cabling complexity in the ROADM 10. A firsttype of FIM (FIM1) 76-1, 76-2 is used for connection to four ports ofthe LA components 72. A second type of FIM (FIM2) 78-1, 78-2, 78-3,78-4, 78-5 is used for connection to eight ports of the LA components 72and MD components 74.

The FIMs may function as an intermediate connector and may be referredto as a “shuffler” in some environments. For instance, each FIM may havefour sub-fiber pairs within each cable and the cables are used tosimplify the connection with a large number of ports. The four sub-fiberpair may connect to different components or circuit packs and can besplit up and redistributed as needed. A FIM may be passive module thatis used for providing connections. The FIM is primarily utilized forcreating a more organized interconnection structure as opposed todisorganized spaghetti interconnections. The FIM1s 76 may be configuredto interconnect up to four degrees via MPO cables. The FIM2s 78 may beconfigured to use MPO cables to interconnect a group of four degrees toanother group of four degrees or to connect the group of four degrees toadd/drop interconnections between LAs and MDs.

According to one example of user provisioning of the section 70,Mode=Focused+MPO identifier. The query results may occur “instantly” inthe CV Rx objects (e.g., MD components 74) or site summary. In oneembodiment, the LA component 72-2 may be referred to as a “leader” (ormay alternatively be referred to as a “master,” “primary,” etc.)component and the first four MD components 74-1, 74-2, 74-3, and 74-4may be referred to as “follower” (or may alternatively be referred to asa “slave,” “secondary,” etc.) components.

In some embodiments, a user (e.g., technician, installer, maintenanceperson, etc.) may specify a single MPO that is undergoing maintenance.This particular identification of an MPO may be interpreted by thepresent systems as an indication that the specific MPO is to be handledin a certain way such that the CV scan can be focused just on this oneMPO. One objective in this case is for the user to verify theconnectivity of the MPO to the right port. Also, another objective is todetermine whether or not the measured fiber loss on both transmit andreceive directions after being serviced does not exceed a certainpredetermined threshold.

The involved nodes may be configured to automatically form a“leader/follower” (or master/slave) formation using peer-to-peermessaging. For example, a single MPO cable can typically accommodate sixfiber pairs where five pairs can be used for degree connections to fivedifferent nodes, and one pair is used for CV communication. In otherwords, when an MPO port is identified as the focus of inspection in theCV scan, the transmit node (e.g., LA component 72-2) will be the leaderthat will communicate with five other downstream nodes to enter a“listening” mode for the followers (e.g., MD components 74).

A Core Transport Manager (CTM) device (with a specific MPO undermaintenance) becomes the “leader” and signals other shelves to enter a“follower” mode which stops autonomous Tx/Rx scanning. At the leadershelf, the CTM device configures a Tx and Rx port-sequence to only scansub-ports associated with the MPO undergoing maintenance. Followershelves may be configured to determine which ports to focus on based onthe leader shelf sub-fiber link provisioning and to focus their Tx andRx ports toward the leader MPO under maintenance using theport-sequence.

The CV method in this embodiment can be applied to homogeneous and/ordisaggregated nodes. For homogeneous nodes with communications betweeninterconnected shelves, messaging between nodes may be transported viainternal device communications. For disaggregated nodes, additionalinformation may be inserted on the CV packets to signal a far-end nodeto enter into a “follower” mode and focus only on Tx/Rx ports where the“follower” indication is received. This mode may be invoked after CVdiscovery has run at least once to discover all the site neighbors.

The MD components 74 at the bottom of FIG. 3 may represent two sets offour circuit packs that correspond with and are connected to one of thefour LA components 72 in a first or second set shown at the top of FIG.3. Connections are arranged such that each MD component 74 is able toreach the four corresponding LA components 72. This connectivity is doneby splitting and reassembling.

The FIM1s 76 and the FIM2s 78, as represented as multiple boxes in FIG.3, may actually be arranged within a single box and may be designed formultiple groups of connectivity. For example, with a four-degree node,the node may be arranged with FIM1s 76 only to handle up to fourdegrees. As shown in the eight-degree (8D) node (e.g., section 70) ofFIG. 3, FIM1s 76 and FIM2s 78 may be needed for more than a four-degreenode. The FIM2s 78 can be installed to create a block so four degreescan be interconnected with another four degrees via the FIM1s 76 and/orFIM2s 78. The FIM1s 76 and FIM2s 78 may have different functions. Forexample, the FIM1s 76 may be configured to connect four elements amongstthemselves, where the FIM2s 78 may be configured to connect fourelements with four different elements.

A user (e.g., technician, installer, engineer, or other operator in thefield of optical networks) may need to disconnect one or more MPOs on aperiodic basis to clean them up. Then, when the MPOs are reconnected,the continuous CV scan would normally be used to check that theinterconnections are proper. However, the embodiments of the varioussystems and methods of the present disclosure are configured toaccelerate the CV testing by focusing a new type of CV scan just on theone or more MPOs that have been reinstalled. Thus, the CV scan time canbe significantly reduced to test the immediately reinstalled connectorsthat the connections are good and the ports are properly matched upaccording to the intended design. In the example shown in FIG. 3, oneMPO connector cable may be connected to four different degrees (e.g., LAcomponents 72) or four different downstream add/drop components (e.g.,MD components 74). The CV test in this case can verify that theconnections of the immediately installed (or reinstalled) MPO cable aregood.

In an environment where the optical network is arranged with ahomogeneous platform, where communication is possible with downstreamshelves/nodes (regardless of who manufactured each independentshelf/node), the focused CV as described in this example can be executedwithout dependency on inter-node or inter-shelf communication (evenwithout a master/slave combination). A user may request a CV scan on thenewly reconnected cable. In this case, the control systems of thepresent disclosure (e.g., controller 50) may be configured to notifydownstream nodes/shelves that a special CV process is planned and thatthe downstream components should listen for specific CV signals.Essentially, this process dynamically creates or establishes aleader/follower (master/slave) arrangement. The request for such aspecial CV scan includes instructing the downstream components to stop anormal CV scanning process and immediately focus attention on one ormore of the new CV techniques (e.g., the process described with respectto FIG. 3).

Thus, the new CV interrupts (or preempts) the full 34-minute scan to runthe rapid CV scans described herein. Temporarily, the leader (e.g., LA72-2) may preempt a full scan and scan only those four ports that arerelevant to the MPO that is under maintenance. Then, the LA 72-2 in thiscase may broadcast that an alternative CV has been entered such that thefollower components (e.g., MD components 74-1, 74-2, 74-3, 74-4) arenotified that the leader has entered this state. In response, thefollowers preempt their full scans and only focus on the single portthat is connected back to the leader. When this operation is done, theleader (e.g., LA component 72-2) may switch back to the regular full CVmode by removing the initial interruption signal (or unblocking thepreemption) to allow the various involved components to resume withtheir normal scans. It should be noted that the leader may be either adegree component or an add/drop component and the follower may be eithera degree component or an add/drop component.

This focused CV scanning can be performed in completely disaggregated orfull homogeneous configurations. If multiple MPO connector cables areremoved and reinstalled at about the same time, the focused CV scanningmay run for each of the MPO cables in a serialized manner (i.e., one ata time).

FIG. 4 is a flow diagram illustrating an embodiment of a process 80 forperforming a CV scan that is focused on an MPO of a ROADM. The process80 may include instructions embodied in the focused CV scanning module64 shown in FIG. 2 for enabling the processing device 52 to perform afocused CV scanning procedure. In this embodiment, the process 80includes a first step of receiving a request to perform a focused CV onone or more communication cables after the one or more communicationcables are physically connected or reconnected into a portion of anoptical network, as indicated in block 82. The process 80 also includesinterrupting an ongoing CV running in the portion of the opticalnetwork, as indicated in block 84, and executing the focused CV totarget a CV scan on the one or more communication cables, as indicatedin block 86.

Block 82 may include targeting the CV scan on the one or morecommunication cables after the one or more communication cables arephysically connected or reconnected into a network node arranged in aportion of a network. In an optional step, the process 80 may furtherinclude resuming the ongoing CV that had been interrupted after thefocused CV is complete, as indicated in block 88. The process 80 mayexecute the focused CV procedure, according to some embodiments, toreduce a cycle time compared with the ongoing CV. The focused CV and theongoing CV may include transmitting a CV packet from a transmitter (Tx)to a receiver (Rx), wherein the CV packet may include one or more of anumber of Tx ports in use, a Tx dwell time, a total Tx scanning time,and a Rx port identifier.

According to some embodiments, the network node may be a ROADM (e.g.,ROADM 10, section 70, etc.). Each of the one or more communicationcables may be physically connected or reconnected between a firstcomponent of the ROADM and a second component of the ROADM. The firstcomponent may be a degree component (e.g., degree component 12, LAcomponent 72, etc.) and the second component may be either a degreecomponent or an add/drop component (e.g., add/drop component 14, MDcomponents 74, etc.). The connecting (or reconnecting) of the one ormore communication cables can be configured to create a leader/followerformation, where one of the first or second components is established asa leader and the other of the first or second components is establishedas a follower. Thus, the degree components can be either a leader or afollower and the add/drop components can be either a leader or afollower. The one or more communication cables may include one or moreMulti-fiber Push-On (MPO) connector cables. From the perspective of CV,the communication cables are considered to be the same, regardless ofwhether they are a degree-to-degree connection or a degree-to-add/dropconnection.

The process 80 may further include the steps of a) detecting atransmission power at a CV source near one end of the one or morecommunication cables, b) detecting a reception power at a CV receivernear an opposite end of the one or more communication cables, and c)calculating a signal loss through the one or more communication cablesbased on the transmission power and reception power. The process 80 mayalso include executing the focused CV by comparing the signal loss witha predetermined threshold to determine if a connection between the CVsource and the CV receiver is acceptable. Also, the process 80 mayinclude skipping a step of checking for other connections in response todetermining that the connection is acceptable. The network in which thenetwork node is configured may be a homogeneous network or adisaggregated network.

Process Using Known Good Packets

FIGS. 5A and 5B are schematic diagrams illustrating an embodiment ofanother section 90 of a ROADM (e.g., ROADM 10 of FIG. 1) for executing afull-node, optimized CV scan for avoiding known good connections toreduce CV processing times. The section 90 of the ROADM of FIG. 5 showsLA components 92, 94 at two degrees (e.g., Degree 1 and Degree 2)interconnected via a Fiber Interconnect Module (FIM) 96. For example,according to the embodiment of FIG. 5 and according to other variousembodiments described throughout the present disclosure, the FIM 96 maybe configured as a photonic module, such as a pluggable Optical TimeDomain Reflectometer (OTDR) module, a pluggable amplifier module, aROADM module, a line interface module, a channel mux/demux module, etc.The FIM 96 may be configured in a reconfigurable line apparatus orsystem that is built on a packet/optical platform, Optical TransportNetwork (OTN), switch, router, shelf, chassis, etc.

FIG. 5A shows the section 90A that is utilized in a conventional manner.For example, a CV algorithm may use relative CV Rx power to distinguishbetween real connections and “ghost channels” due to WSS crosstalk.However, this may require collecting detected packets for all possibleTx/Rx combinations, then selecting the packet with the highest Rx poweramong all packets sharing the same Tx or Rx port. In the worst casescenario, as mentioned above, it can take nearly two full CV cycles(i.e., 2×17 minutes) to make a final decision. This conventional CVmethod is run when a new connection is made and when the CV Rx has justswitched to the next port.

FIG. 5B illustrates the novel CV algorithm according to the variousembodiments of the present disclosure. The section 90B may use anabsolute CV Rx power to identify “known good packets.” A “known goodpackets” threshold may be defined by the highest possible ghost power(e.g., max Tx power, min Insertion Loss (IL), min WSS isolation, etc.).Since the connections with an acceptable loss (e.g., less than about 6to 10 dB) are identified immediately, the present processes can speed upthe CV scan by a factor of up to four. As soon as a good connection hasbeen identified, the CV Rx can move on to the next port instead ofwaiting a fixed dwell time (as is done in conventional algorithms). Highloss connections (e.g., greater than about 6 to 10 dB) may still requirethe full CV cycle.

This embodiment may include performing the speedy CV process when portsare already known to be in service (i.e., carrying traffic). In thiscase, it may not be necessary to scan again and again, since thearrangement is known. By skipping paths based on what is known, the CVprocessing time can be reduces by reducing the overall dwell time.

Process of Skipping Non-Provisioned Tx and Rx Ports

FIG. 6 is a graph 100 illustrating the CV reception (Rx) power reading(in dBm) related to executing the CV scan with respect to FIG. 5B. Thegraph 100 shows “connection,” “far end Tx ghost,” and “local Rx ghost”portions. Also, the graph 100 includes a typical CV Rx power at about−20 dBm and a known good packet threshold at about −30 dBm. Portionsbelow about −30 dBm may be referred to as “ambiguous Rx powers.”

Unused ports (e.g., MPO connectors capped with dust caps) can be skippedbased on link provisioning. The process of skipping non-provisioned Txand Rx ports may include excluding ports without explicit linkprovisioning from Tx and Rx port scan sequences. Also, link provisioningmay be enforced by a user at a degree commissioning time. In addition,ports participating in an MPO with at least one sub-fiber linkprovisioned would not normally be excluded in these examples. However,fibers in MPOs where no ports have links provisioned can be skipped.

To get the full benefit of skipping ports of the N² ports, the Rx dwelltime can be scaled across the node. This would utilize knowledge of Txscan characteristics of the cards connected to a given Rx card. In someembodiments, the processes in this example may communicate via a CVprotocol the number of Tx ports being scanned and the Tx dwell time.Each card may collect this information from all its neighbors. Theworst-case values across all connected cards, in some cases, may be usedby a Core Transport Manager (CTM) to derive the Rx dwell time for agiven card.

Skip In-Service Ports to Reduce Rx Dwell Time

The card (e.g., switch) may automatically skip Rx ports which have inputLoss of Signal (LOS) cleared and have a discovered port-ID. In thisstate, all the discovered data and timestamps may be latched. The totalCV time becomes:(N _(MaxRx) −N _(Loopback) −NIS)×NTX×Tx_dwell_time,where N is the number of Tx or Rx ports. The process may includeclearing latched data if anytime the LOS is raised and returning thedata back into scan until the above conditions are met again.

The process may also include skipping Tx ports if a demux switch-outport has LOS cleared and if the far end “received-port-ID” has beenreceived. In this case, some embodiments may include sending the“received-port-ID” as part of the CV transmit packet. If a port seesthat the corresponding far-end port has received a packet that it sent,then that transmit switch-out port is considered as “verified” and isskipped from further scanning until a LOS (or an Automatic PowerReduction (APR)) is raised again.

The method of skipping in-service ports may be applicable for bothhomogeneous and disaggregated solutions if the interconnected degreefiber loss can be measured (internally or externally) based on totalpower deltas. These measured losses may also be taken into accountinstead of just relying on CV Tx/Rx power deltas. If the interconnecteddegree fiber loss cannot be measured, the processes may not be able toskip these in-service ports according to this example.

Transmitting Received Port ID

FIG. 7 is a diagram showing an embodiment of a transmission flow 110 ofport identification (port ID) messages with respect a CV scan. In thisembodiment, the transmission flow 110 may involve skippingnon-provisioned Tx and Rx ports. A first CV Tx component 112 may beconfigured to send a “transmit-port-ID” message to a first CV Rxcomponent 114. The first CV Rx component 114 may include anexpected-port-ID, but receives the transmit-port-ID message from thefirst CV Tx component 112 as an “actual-port-ID.” This is sent to asecond CV Tx component 116 as a “far-end-Tx-port-ID,” which in turn istransmitted to a second CV Rx component 118 as an “actual-port-ID.”Also, the second CV Tx component 116 sends a “transmit-port-ID” to thesecond CV Rx component 118, which has an “expected-port-ID” but receivesthe “transmit-port-ID” from the second CV Tx component 116 as an“actual-port-ID.” This is then sent to the first CV Tx component 112 asa “far-end-Tx-port-ID,” which in turn is transmitted to the first CV Rxcomponent 114 as a “far-end-Rx-port-ID.” On CTM equipment, if a localtransmit-port-ID=far-end-Rx-port-ID, then this may be interpreted as aguaranteed that the local transmit port is connected to far end. Thisprovides an advantage of guaranteeing connections even if the MPO portsare split into LC connections.

Improvements to “Known Good Packets” Algorithm

According to some embodiments, the CV scans may be implemented toprovide further improvements to “known good packets” algorithm, if thisalgorithm is combined with skipping in-service ports (i.e.,traffic-carrying ports). Since in-service ports can be skipped fromscanning in some cases, then this embodiment may be configured toidentify “good packets” based on CV measured fiber loss rather thanabsolute Rx power, which will give a much higher contrast between realpackets and ghost packets. The point in this case is that if there isreal traffic going through a node, the CV algorithm could be fooled intothinking that a ghost packet is seeing low fiber loss (or even gain)because the photodiodes would mostly see the signal power. In theabsence of a signal, the measured fiber loss will be high (+20 dB) for aghost packet compared to a real one.

According to one example for performing the known good packetsalgorithm, a card (e.g., Card A) may have CV Tx switch to port 1, butsome light (e.g., about −20 dB) may leak into port 2, which is connectedto port 3 of Card B. If there is no traffic, the dark fiber InsertionLoss (IL) detected in Card B will be greater than 20 dB since the CVpacket from Card A would contain a value from port 1 (obtained by anoptical monitor), whereas an optical monitor for the port 3 of Card Bmay provide a power that is at least 20 dB lower. If there is traffic,then the readings from the two optical monitors may be dominated bysignal power and the calculated fiber loss may be a random numbercomparing Card A port 1 to Card B port 3. However, with this method, itis possible that the CV processes may be guaranteed to have about 20 dBdifference between a real packet and a ghost so that the real packetscan be identified, even if the fiber loss is very high (e.g., up toabout 15 dB).

Skipping Unused Ports with Loopback Connectors

FIG. 8 is a schematic diagram showing an embodiment of another section120 of a node (e.g., ROADM 10 of FIG. 1) of an optical network. Aprocess for executing another CV scan may involve skipping unused MPOports by utilizing loopback connectors. The section 120 includes a ROADMwith a Line Amplifier (LA) 122. For example, the LA 122 may beconfigured as a 32×1 C-band with OTDR 1×SFP. Among other components, theLA 122 may include a WSS multiplexer 124 (e.g., 32:1 MUX) and a WSSdemultiplexer 126 (e.g., 1:32 DEMUX). MPO cables 128, 130 may beconnected with FIM 132. The MPO cable 128 may be connected to one of theconnector terminals 134 of the WSS demultiplexer 126 and the MPO cable130 may be connected to one of the connector terminals 136 of the WSSmultiplexer 124.

As shown in this example, one of the connector terminals 134 isconnected to an MPO cable 138 having loopback connections 140 via theFIM 132. Also, one of the connector terminals 136 is connected to an MPOcable 142 having loopback connection 144 via the FIM 132. In theembodiment of FIG. 8, the remaining connector terminals 134, 136 may beconfigured with loopback connections 146 without the use of the FIM 132.

According to a CV method with the loopback connections shown in FIG. 8,link provisioning may not be required for CV optimization. The loopbackconnectors are positioned on the unused ports for optimized performance.In some embodiments, all the unused ports may be connected to some typeof loopback connector.

In a loopback pre-scanning process, the CV method may implement atwo-phase enhanced scan where Tx and Rx scan cycles are pre-empted torun initially in lock-step before entering the standard cycle ofscanning Tx and Rx independently. The loopback pre-scan may begin at thestart of an enhanced scan cycle. The Tx and Rx components may be locallyconfigured to synchronously scan all switch ports in sequence. Since theTx and Rx components may be focused on each other, the dwell time can beminimal (e.g., about one second) and the ports can be scanned in shortorder. For example, pre-scan may last about four seconds per connectorterminal 134, 136 such that, with eight connector terminals 134, 136,the total pre-scan time will be about 32 seconds for a 1×32 LA. Duringthe pre-scan, Tx/Rx pairs which match may be identified as loopback andcan be excluded from the independent CV scan phase.

In some embodiments, the loopback connectors can be deployed as is shownin FIG. 8. In this case, the CV described with respect to FIG. 8 mayinclude quickly scanning ahead of time to see which paths loop back andwhich ones can actually be reconnected. With this initial test, it ispossible to focus on only the reconnectable ones as they are beingreconnected and simply avoid the loopback ones.

This loopback pre-scan process may further be configured such that asecond phase scan may be similar to other scans except that the totaltime may be:(N _(MaxRx) −N _(Loopback))×NTX×Tx_dwell_timeFor example, with only one quad group populated, the scan time might be(32−24)×(32)×(1 second)=256 seconds (or 4.3 minutes), as opposed to 17minutes in conventional algorithms. The total time (with the 32 secondpre-scan time) may include:32 seconds (pre-scan)+256 seconds (CV scan)=288 seconds (about 4.8minutes)

This total cycle time would be associated with a four-degree node. Whena new degree is inserted, the loopback pre-scan may be manuallyinitiated on nodes that are already in service.

Advantages of New CV Modes

FIG. 9 is a chart 150 illustrating examples of expected times forrunning the various CV scans on an optical node (e.g., ROADM 10 ofFIG. 1) according to the various processes described in the presentdisclosure. The chart 150 also shows a comparison with a conventionalmethod. Also, comments (which may also include the correspondingexplanations described above with respect to each respective technique)are also provided in the chart 150. The total CV scan times are shownfor a four-degree (4D) node, an eight-degree (8D) node, and a 16-degree(16D) node are included.

In particular, the chart 150 shows that the conventional CV time may beabout 25 minutes. A “full node, optimized” method (which may correspondto the embodiments described with respect to FIG. 5) results in adecrease in CV scan time down to about 15 minutes, 13 minutes, and 9minutes for the 4D, 8D, and 16D nodes, respectively. A “skipnon-provisioned ports” method (which may correspond to the embodimentsdescribed with respect to FIG. 7) results in a decrease in CV scan timedown to about 0.5 minutes, 2.1 minutes, and 8.5 minutes for 4D, 8D, and16D nodes, respectively. A “skip non-loopback ports” method (which maycorrespond to the embodiments described with respect to FIG. 8) resultsin a decrease in CV scan time down to about 1 minute, 2.4 minutes, and8.5 minutes for the 4D, 8D, and 16D nodes, respectively. A“troubleshooting” method (which may correspond to the embodimentsdescribed with respect to FIG. 3) may be a preferred method that resultsin a decrease in CV scan time less than about 10 seconds for each of 4D,8D, and 16D nodes.

In summary, conventional systems may include CV algorithms that runcontinuously on reconfigurable line platforms. The embodiments of thepresent disclosure may be incorporated into existing platforms or newerplatforms as well where receivers/terminators may be in communicationwith FIMs. The new CV algorithms may be run in a disaggregatedenvironment, such as where one device (e.g., a MUX) may be manufacturedby one company and another device (e.g., a DEMUX) may be manufactured byanother company. One of the goals of a disaggregated environment is tosupport CV with integrated connection verification from any givendegree.

For CV, a laser Tx source may be implemented on one side (e.g., a MUXside) and may keep transmitting CV signals sequentially on every port.On the Rx side, each port may be configured to continue looking for acertain amount of time to see if the CV Tx signal is received, and thenthe waiting process moves on to the next port, and so on, until eachdifferent port has a chance to determine the connectivity. The CVprotocol includes a single Tx source and every individual Rx terminationthat is essentially blind to the source. There is no predeterminedcoordination, which requires a test on each possible path from thesingle Tx source to the multiple Rx terminations. Thus, the total CVscan time is dependent on the number Tx and Rx ports. For example, theremay be 20 switch ports on the Tx side where each switch port takes abouta second to broadcast its CV signal. On the Rx side, each port maycontinue searching for at least about 30 seconds to make sure that theTx level is complete, before moving on to the next Rx switch port. Bywaiting for a source signal for a long enough time (based on the numberof Tx ports and Tx dwell times), the Rx will eventually receive the Txsignal. In contrast, however, the embodiments of the present disclosuremay utilize a similar architecture but may instead use different typesof CV processes, as described above, to overcome the limitations of theconventional methods in order to reduce the total CV times.

The CV algorithms described in the present disclosure have novelty withrespect to conventional CV methods. For example, the present CVprocesses can create a dynamic leader/follower (e.g., master/slave)formation among interconnected degree nodes in a consolidated setupwithout a shelf/chassis identifier to allow a focused debugging on agiven MPO cable. The present CV processes also introduce the concept ofskipping unused ports, which may save a lot of time in a high port countROADM node for a regular mode of operation and also introduce theconcept of populating unused ports with loopback connectors so that acard can quickly and independently determine which ports are unused.

The novel concept of skipping already in-service ports may be based onan assumption that in-service ports are already carrying traffic and donot require further connection validation if degree fiber loss can bemeasured (externally or internally) based on total power deltas, ratherthan relying on CV Tx/Rx powers. Also, the novel CV processes describedherein provide received port-IDs as part of a transmit packet, whichallows in-service ports to be skipped, even in a transmit direction.Also, the present embodiments have novelty in that they provideadditional Tx information to optimize the Rx dwell time. Another novelfeature is that a known good IL or power threshold that eliminates theneed to filter for ghosts may allow the Rx listening to move immediatelyto a next port instead of waiting an entire Tx dwell time.

Although the present disclosure has been illustrated and describedherein with reference to exemplary embodiments providing variousadvantages, it will be readily apparent to those of ordinary skill inthe art that other embodiments may perform similar functions, achievelike results, and/or provide other advantages. Modifications, additions,or omissions may be made to the systems, apparatuses, and methodsdescribed herein without departing from the spirit and scope of thepresent disclosure. All equivalent or alternative embodiments that fallwithin the spirit and scope of the present disclosure are contemplatedthereby and are intended to be covered by the following claims.

What is claimed is:
 1. A controller configured to manage ConnectionValidation (CV) in a portion of an optical network, the controllercomprising a processing device, and a memory device in communicationwith the processing device, the memory device configured to store acomputer program having instructions that, when executed, enable theprocessing device to receive a request to perform a focused CV on one ormore communication cables after the one or more communication cables arephysically connected or reconnected into a network node arranged in theportion of the optical network, interrupt an ongoing CV running in theportion of the optical network, and execute the focused CV to target aCV scan on the one or more communication cables.
 2. The controller ofclaim 1, wherein the instructions, when executed, further enable theprocessing device to resume the ongoing CV after the focused CV iscomplete.
 3. The controller of claim 1, wherein the network node is aReconfigurable Optical Add/Drop Multiplexer (ROADM).
 4. The controllerof claim 1, wherein each of the one or more communication cables isphysically connected or reconnected between a first component of aReconfigurable Optical Add/Drop Multiplexer (ROADM) and a secondcomponent of the ROADM, wherein the first component is a degreecomponent and the second component is one of an add/drop component andanother degree component.
 5. The controller of claim 4, wherein theinstructions, when executed, further enable the processing device tocreate a leader/follower formation where one of the first and secondcomponents is established as a leader and the other of the first andsecond components is established as a follower.
 6. The controller ofclaim 1, wherein the one or more communication cables include one ormore Multi-fiber Push-On (MPO) connector cables.
 7. The controller ofclaim 1, wherein the instructions, when executed, further enable theprocessing device to detect a transmission power at a CV source near oneend of the one or more communication cables, detect a reception power ata CV receiver near an opposite end of the one or more communicationcables, and calculate a signal loss through the one or morecommunication cables based on the transmission power and receptionpower.
 8. The controller of claim 7, wherein the instructions, whenexecuted, further enable the processing device to execute the focused CVby comparing the signal loss with a predetermined threshold to determineif a connection between the CV source and the CV receiver is acceptable,and skipping a process of checking for other connections in response todetermining that the connection is acceptable.
 9. The controller ofclaim 1, wherein the optical network is configured as one of ahomogeneous network and a disaggregated network.
 10. The controller ofclaim 1, wherein executing the focused CV reduces a cycle time comparedwith the ongoing CV.
 11. The controller of claim 1, wherein the focusedCV and the ongoing CV include transmitting a CV packet from atransmitter (Tx) to a receiver (Rx), and wherein the CV packet includesone or more of a number of Tx ports in use, a Tx dwell time, a total Txscanning time, and a Rx port identifier.
 12. A method comprising thesteps of: receiving a request to perform a focused Connection Validation(CV) on one or more communication cables after the one or morecommunication cables are physically connected or reconnected into aportion of an optical network, interrupting an ongoing CV running in theportion of the optical network, and executing the focused CV to target aCV scan on the one or more communication cables.
 13. The method of claim12, further comprising the step of resuming the ongoing CV after thefocused CV is complete.
 14. The method of claim 12, wherein the portionof the optical network includes a Reconfigurable Optical Add/DropMultiplexer (ROADM).
 15. The method of claim 14, wherein each of the oneor more communication cables is physically connected or reconnectedbetween a first component of the ROADM and a second component of theROADM, wherein the first component is a degree component and the secondcomponent is one of an add/drop component and another degree component,and wherein one of the first and second components is established as aleader and the other of the first and second components is establishedas a follower in a leader/follower formation.
 16. The method of claim14, wherein the one or more communication cables include one or moreMulti-fiber Push-On (MPO) connector cables.
 17. The method of claim 12,further comprising the steps of detecting a transmission power at a CVsource near one end of the one or more communication cables, detecting areception power at a CV receiver near an opposite end of the one or morecommunication cables, and calculating a signal loss through the one ormore communication cables based on the transmission power and receptionpower.
 18. The method of claim 17, wherein the step of executing thefocused CV includes the steps of comparing the signal loss with apredetermined threshold to determine if a connection between the CVsource and the CV receiver is acceptable, and skipping a process ofchecking for other connections in response to determining that theconnection is acceptable.
 19. A node of an optical network, the nodecomprising: a Connection Validation (CV) source of a first component;and a CV receiver of a second component configured to perform CV scanson one or more communication cables, the CV source and CV receiver areconfigured to receive a request to perform a focused CV on the one ormore communication cables after the one or more communication cables arephysically connected or reconnected between the first component and thesecond component, interrupt an ongoing CV running between the firstcomponent and the second component, and execute the focused CV to targeta CV scan on the one or more communication cables.
 20. The node of claim19, wherein the CV source and CV receiver are configured to resume theongoing CV after the focused CV is complete.